Novel Approach for the Reduction of ZnO and MgO Using a Direct Diode-Laser
- PDF / 2,058,524 Bytes
- 8 Pages / 593.972 x 792 pts Page_size
- 57 Downloads / 177 Views
N
RENEWABLE energy is an effective alternative source of energy; therefore, efforts are now devoted to the development of sustainable processes of harvesting and storing this energy. For example, the solar energy strikes the earth’s surface at a continuous rate of 1.2 9 105 TW, which vastly exceeds our current worldwide power demand of 17 TW.[1] The drawback is that it is intermittent and diffuse. The average hours of sunshine are 4 hours/day in Japan; therefore, the solar energy must be stored in some energy carrier. One solution for these problems is converting the light energy to a storable chemical fuels, including H2, reduced carbon compounds, metals, or other compounds.[2–6] The use of the thermochemical energy enables the 24-hours energy production from solar power plants. It also offers an effective way for energy transporting. There exist several candidates for storing the solar energy or other energy. Nevertheless, it is important to note that three major points must be cleared: (1) It must be transportable; (2) the employed materials must be abundant; and (3) the process should not harm the environment.
M.S. MAHMOUD, Associate Professor, is with the Chemical Engineering Department, Faculty of Engineering, Minia University, Minia 61516, Egypt. Contact e-mail: [email protected] T. YABE, formerly Professor Emeritus with the Mechanical Engineering Department, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro, Tokyo 152-8552, Japan, is now Head with Energy Genesis Cycle, 405 East Wing, 3-2-1 Sakado, Takatsuku, Kawasaki City, Kanagawa 2130012, Japan. E. IIDA, formerly Member with Energy Genesis Cycle. Manuscript submitted January 8, 2016. METALLURGICAL AND MATERIALS TRANSACTIONS B
We proposed Mg as energy storage metal along with solar-energy-pumped lasers[5,7] because Mg is an abundant element in the earth’s crust; also, it is the second richest metal element in sea water with a concentration of 1.3 g/L. In addition, we studied a new technique to make the Mg battery economically feasible.[8] At the anode, magnesium oxidized to give Mg+2 and two electrons, while at the cathode, a typical oxygen reduction reaction took place. Two major technical barriers were addressed: the products at the anode deposit over its surface hindering the oxidization of Mg to proceed, and the oxygen reduction reaction is known to be a slow kinetic reaction since it involves a three-phase catalytic reaction. To overcome those barriers, the Mg battery was made to resemble the video tape, where it consists of the reaction chamber and Mg thin tape. After consuming the thin tape in the reaction chamber, the reaction products Mg(OH)2 and/or MgO are moved away from the chamber and the new film automatically enters into the chamber by winding the film using some mechanism like a spring or small motor. We calculated the battery capacity by using such thin Mg film to be 1300 Ah/kg, which is nine times larger than 150 Ah/kg of a Li-ion battery.[8] Furthermore, the theoretical specific energy density of Mg battery is 6.8 kWh/kg, which is higher
Data Loading...
